Artificial teeth and means for fixing the same



Sept. 25, 1928.

' 1,685,541 C. JOANNIDES ARTIFICIAL TOOTH AND MEANS FOR FIXING THE SAME Filed Dec. 27. 1920 Fwd 1. 12m 12 1. iz i d Patented Sept. 25, 1928.

UNITED. STATES PATENT OFFICE.

oimisrnJoA NmnEs, or LONDON, ENGLA ARTIFICIKL J AND MEANS FOR {FIXING THE Application filed December 27, 1920, Serial 1T0. 433,418, and in Great Britain January 13, 1920.

The present invention relates to artificial teeth.

It is the general object of the invention to more securely fasten artificial teeth to their backing.

For a full understanding of the invention, its characteristic features and advantages, reference is made to the accompanying drawings in which Fig. 1 is a sectional view of a tooth embodying the. invention Fig. 1 is a rear view thereof, partly in section;

Figs. 1 and 1 are rear views showing modifications of detail; and

Fig. 1 is a sectional view showing another form embodying the invention; and

Figs. 29 are similar views showing various modifications.

Having reference to Fig. 1, (1. represents the usual porcelain body of the tooth and the dotted line b indicates the backing of red rubber or of any suitable composition to which the tooth is attached by a pin 0 having a head 0 in the backing. The pin is inclined to the face of the tooth and is curved in the tooth toward the tip thereof. The cross-sectional area of the pin is elongated, being longer in the direction'of'length of the tooth than transversely thereof.

The significance of this construction is as follows:

-The greater cross-sectional dimension of the pin in the direction of length of the tooth affords a greater shearing resistance, since the shearing stresses are principally transmitted in the direction of length of the tooth. Secondly, the weakening efiect which the mounting of the pin has upon the body of the tooth is greatly reduced because the reduc tion of the dimension of the pin transversely of the tooth correspondingly increases the strength of the tooth in the direction in which the tooth is naturally weakest. In addition, the angular relation of the pin increases resistance against shearing or breaking. In the first instance,,the inclined position increases the shearing area, but the principal factor is the partial transmission of the stresses, which normally occur in the direction of length of the tooth, along the pin whereby the shearing stress is correspondingly reduced.

As indicated in Figs. 1 and 1", two pins may be used as was heretofore the practice, or a single pin may be applied, as indicated in Fig. 1.

There is a great deal of latitude as to the specific details. Above all, the pin portion outside the tooth or in the backing may have any desired form. In practice I prefer to make it as sturdy as possible. There is no restriction whatever in this respect. The

pin'thus may be round or angular in the backing.

lVhile the concurrence of the various features as described in connection With Fig. 1 is instrumental in producing a particularly good construction, the several features may be separately incorporated. Thus, as indicated in Fig. 1, the pin is not inclined, but enters the tooth substantially at right angle, as was heretofore the practice. However. the flattened portionwithin the tooth, as'de scribed in connection with Fig. 1, increases the strength of the tooth. On the 'other hand, the inclination of a round pin, as for instance. indicated in Figs. 8 and 9, increases the strength of the connection as explained.

In practice I prefer, of course, the concurrent application of the two features to derive a maximum of resistance of tooth and connection. 7 V

In the arrangement as shown in Fig. 4, the pin lies level or horizontal, is flat inside the tooth, and tapers down in width towards its head C, the part outside the tooth being round in cross section as in Figs. 1 to 3.

As is particularly apparent from Fig. 7, the portion of the pin inside the tooth may be disposed horizontally, while the portion in the backing may be inclined-to the tooth.

The anchoring of the pin in the tooth may be effected in various ways. As indicated in Figs. 1 and 5, the pin may be curved to safely secure it. In the form shown in Fig. 9 no special means are provided. Due to the inclination the in extends a greater distance into the toot and the angular position affords an anchoring effect. However, a head may be provided in various ways, as indicated in various figures. 1

In practice I prefer to have the head c in the backing inclined or disposed in a plane approaching parallelism to the exsential features of the invention as they may be incorporated separately or together in various forms. a

I claim:

An artificial tooth having a rigid pin for attachment to a backing,the portion of the" pin Within the tooth being elongated in cross-section in the direction of the length of the tooth; and the portion of the'pin exterior of the tooth merging gradually from said elongated section to a circular cross-section the two said portionsbeing substantially in axial alignment, the portion of the pin exterior to said tooth terminating in an enlarged head, the axis of which is inclined to the 'axis' of the tooth.

Intestimony whereof I afiix my signature.

CHRISTE JOANNIDES. 

